I don't know about your particular situation, but I have read stories about the possible cause of the increase in asthma and allergies is due to the LACK of exposure to irritants, such as smoke during early childhood.
Working in a room full of cigarette smoke is harmful. Stinks.
The studies at the link I gave you says that second-hand smoke is not harmful in the long run. It does stink to some people and can be an irritant to others. A private business can make a reasonable accommodation, or you can go elsewhere.
There are plenty of important governmental regulations regarding harmful chemicals in the workplace. Just that some are addicted to tobacco is no excuse not to include that among them.
There are too many government regulations. As the article at the link states, "the poison is in the dose". We are confronted with poisons everyday in small doses. Our bodies guard against them and in some cases become more resistant due to exposure.
Why should one have to take a lesser opportunity, when others are being rude and abusive to the point of poisoning one's very air?
BTW, "second hand smoke" isn't all second hand. It includes that which is filtered by another's lungs and that which goes into the air, directly.